Device for measuring critical scintillation fusion frequency

Abstract

The utility model relates to the technical field of measurement, in particular to a device for measuring critical scintillation fusion frequency. The device comprises an LED light source, an EEG acquisition device and a signal processing unit. According to the utility model, the LED light source and the portable EEG head-mounted equipment are ensured to be calibrated to provide accurate stimulation and record, the EEG head-mounted equipment is adjusted to the head of a subject to ensure that the six electrodes are accurately positioned in a visual central area, and the LED light source is started to display flickering light to the subject to perform visual stimulation on the subject, so that the visual stimulation effect is improved, and the visual stimulation effect is improved. As the accuracy of a measurement result may be affected by subjective factors of a subject, in the test process, the electroencephalogram signals of the subject are collected and analyzed to obtain a more objective and more accurate test result, the collected electroencephalogram signals are filtered and denoised through the signal processing unit, and the accuracy of the test result is improved. The features related to visual stimulation are accurately extracted, the effectiveness of the visual stimulation is improved, and the stability of a detection result is improved.

Description

Technical Field

[0001] This utility model relates to the field of measurement technology, and in particular to a device for measuring the critical scintillation fusion frequency. Background Technology

[0002] Critical flicker fusion frequency (CFF) refers to the lowest frequency at which the human visual system perceives flickering light as stable light. When the flicker frequency exceeds the critical flicker frequency, the eye perceives it as stable light. CFF reflects the temporal resolution limit of the visual system and the level of optic nerve function, and is highly sensitive to retinal and optic nerve disorders. When patients have fundus diseases such as macular degeneration, optic neuropathy, glaucoma, or diabetic retinopathy, CFF measurements will decrease; that is, damage to the visual pathway leads to a decrease in CFF. Opacity of refractive media has a limited impact on CFF values ​​because it primarily affects the spatial resolution of the visual system rather than its temporal resolution.

[0003] The cone cells in the retina are mainly L-cones, M-cones, and S-cones, each with different sensitivities to different wavelengths of light (red, green, and blue), and their density is highest in the macula (the area of ​​greatest visual acuity). Cone flicker detection (CFF) of different colors of light can provide multifaceted information about visual function. However, because CFF testing is a subjective examination, its results depend on the patient's subjective perception of the flickering light, thus having some inherent limitations. A patient's cognitive level, reaction time, fatigue level, and concentration can significantly affect the test results. For example, patients with low cognitive levels, poor concentration, prolonged visual tasks, or physical fatigue may be unable to accurately judge the flicker frequency, leading to decreased reliability of the measurement results.

[0004] EEG (electroencephalography) is a method that records brain activity using electrophysiological indicators. During brain activity, the postsynaptic potentials of a large number of neurons occur synchronously and are summed to form the brainwave changes during activity. It is a comprehensive reflection of the electrophysiological activity of brain nerve cells on the cerebral cortex or scalp surface. In ophthalmological examinations, visual pathway function can be assessed by recording the brain's electrophysiological response to visual stimuli. Traditional EEG examinations use 12 electrodes, while in visual stimulation examinations, only 6 electrodes in the visual cortex are needed. Although EEG provides objective electrophysiological data on the reception of brain electrical responses, it also has certain limitations. When measuring visual stimuli, interference can occur in the presence of turbid refractive media, affecting the accuracy of the results. Therefore, combining CFF (contrast-induced foveation) with EEG—that is, recording the EEG signals of the visual cortex during visual stimulation to form a stimulus-reception loop—can reduce the influence of subjective factors on CFF results, improve the objectivity and accuracy of CFF measurement, and is of great significance for visual function assessment.

[0005] Among existing devices for measuring critical scintillation fusion frequency, there is a lack of a measurement system that combines CFF with a portable EEG device. By acquiring and analyzing EEG signals and adjusting the stimulation frequency based on the analysis results, the inaccuracy of measurement results due to subjective influence can be greatly reduced. Utility Model Content

[0006] Therefore, this utility model provides a device for measuring the critical scintillation fusion frequency, which overcomes the problem in the prior art that there is no measurement system that combines CFF with portable EEG equipment, making the measurement results susceptible to the subjective factors of the test subject, resulting in low measurement accuracy.

[0007] To achieve the above objectives, this utility model provides a device for measuring the critical scintillation fusion frequency, comprising an LED light source, an EEG acquisition device connected to the LED light source, and a signal processing unit;

[0008] The EEG acquisition device includes an EEG head-mounted device and electrodes disposed on the EEG head-mounted device.

[0009] Furthermore, the electrodes are used to conduct electroencephalogram (EEG) signals.

[0010] Furthermore, the LED light source includes a light-emitting module, a sleeve, and a threaded tube sleeved on the outside of the sleeve.

[0011] Furthermore, the LED light source is connected to the EEG acquisition device via a connecting line.

[0012] Furthermore, the signal processing unit is connected to the EEG acquisition device via Bluetooth or WiFi.

[0013] Furthermore, an apparatus for measuring a critical scintillation fusion frequency also includes an operating lever and a feedback module, the feedback module being electrically connected to the operating lever.

[0014] Furthermore, the control lever includes a button and a communication module. The button is electrically connected to the signal processing unit, and the communication module is used to receive CFF feedback data from the button and transmit the CFF feedback data to the signal processing unit.

[0015] Furthermore, the EEG headset remains fixed during the measurement process.

[0016] Furthermore, the electrode is positioned in the visual cortex region.

[0017] Furthermore, the number of electrodes is 6.

[0018] Compared with existing technologies, the advantages of this invention are as follows: by ensuring that the LED light source and portable EEG head-mounted device are calibrated to provide accurate stimulation and recording, by adjusting the EEG head-mounted device to the subject's head to ensure that all six electrodes are precisely positioned in the visual cortex region, and by activating the LED light source to display flashing light to the subject for visual stimulation, the accuracy of the measurement results may be affected by the subject's subjective factors. Therefore, during the testing process, the subject's EEG signals are collected and analyzed to obtain more objective and accurate test results. Furthermore, when the EEG acquisition device records the subject's EEG signals under visual stimulation in real time, since the EEG data is affected by external factors such as the subject's eye movements and muscle movements during the acquisition process, the signal processing unit filters and denoises the collected EEG signals to accurately extract features related to visual stimulation as real-time feature signals. By analyzing the real-time feature signals and using ERP analysis to extract real-time features from the EEG signals, the visual stimulation parameters are dynamically adjusted to improve the effectiveness of visual stimulation and increase the stability of the test results. Attached Figure Description

[0019] Figure 1 A schematic diagram of the device for measuring the critical scintillation fusion frequency provided in an embodiment of this utility model.

[0020] Among them, 1-LED light source, 101-threaded tube, 2-EEG head-mounted device, 3-electrode, 4-signal processing unit, 5-feedback module, 501-button, and 6-connection line. Detailed Implementation

[0021] To make the objectives and advantages of this utility model clearer, the utility model will be further described below with reference to the embodiments; it should be understood that the specific embodiments described herein are only for explaining this utility model and are not intended to limit this utility model.

[0022] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] It should be noted that in the description of this utility model, the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this utility model.

[0024] Furthermore, it should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0025] Please see Figure 1 The diagram shown is a structural schematic of a device for measuring the critical scintillation fusion frequency provided in an embodiment of the present invention. The present invention provides a device for measuring the critical scintillation fusion frequency, comprising:

[0026] LED light source 1 includes a light-emitting module, a sleeve, and a threaded tube 101 sleeved on the outside of the sleeve;

[0027] The EEG acquisition device includes an EEG headpiece 2 and six electrodes 3 positioned in the visual cortex region on the EEG headpiece 2. The EEG headpiece 2 is used to fix and connect the electrodes 3, and the electrodes 3 are used to capture brain signals.

[0028] Connection line 6, one end of which is connected to the threaded tube 101, and the other end of which is connected to the EEG acquisition device;

[0029] Feedback module 5, which is electrically connected to the control lever, generates CFF feedback data based on the triggering result;

[0030] The signal processing unit 4 is connected to the EEG acquisition device via Bluetooth or WiFi. It is used to receive and process the EEG signals from the EEG acquisition device to obtain real-time constant brightness feature signals and real-time flicker feature signals, so as to construct a perceptual flicker dataset and a perceptual constant brightness dataset, and to send a trigger signal to the EEG acquisition device.

[0031] The joystick includes a button and a communication module. The button is electrically connected to the signal processing unit, and the communication module is used to receive CFF feedback data from the button and transmit the CFF feedback moment to the signal processing unit.

[0032] The CFF feedback data includes the CFF feedback time.

[0033] A critical scintillation fusion frequency value calculation unit, which is connected to the feedback module and the signal processing unit, is used to analyze the perceived scintillation dataset based on the CFF feedback data to determine the critical scintillation fusion frequency value.

[0034] In this embodiment, before the measurement begins, the machine automatically calculates and adjusts the required cursor size, light intensity, and measurement distance. Finally, the doctor manually checks if the cursor is directly in front of the cornea. The subject holds a control lever with buttons. The subject uses the lever to indicate whether they perceive flickering / constant light. Each time the machine adjusts the frequency, it emits a "beep." If the patient perceives flickering after hearing the beep, they briefly press the control lever button; if they perceive constant light, they press and hold the button. During the measurement, the signal processing unit correlates with CFF feedback data and analyzes the collected EEG signals to avoid the influence of the subject's subjective factors on the test results, accurately identifying perceived and unperceived results to obtain the critical flicker fusion frequency value. During the measurement, the flicker frequency of the visual stimulus is controlled from 0Hz, increasing in increments of 2Hz. The frequency is initially increased from 0.5 Hz. During this increase, feedback results are obtained. When no flicker feedback is received, the frequency is decreased by 1.5 Hz until another perceptible feedback result is obtained. Then, the frequency is increased by 1 Hz until no flicker feedback is obtained, at which point the current flicker frequency is obtained and used as the target perceptual result. The current flicker frequency is then verified by decreasing it by 1 Hz once to obtain the first verified perceptual result, and increasing it by 1 Hz once to obtain the second verified perceptual result. The average of the actual measured frequencies corresponding to the target perceptual result, the first verified perceptual result, and the second verified perceptual result is taken to obtain the critical flicker fusion frequency value. In this embodiment, the preset stimulus duration represents a period of time after the stimulus occurs, and an important stage of visual information processing is involved within the preset stimulus duration. Generally, the preset stimulus duration is set in the range of 200 milliseconds to 600 milliseconds to effectively capture the brain's response pattern to visual stimuli. The initial flicker frequency is set to 0 Hz.

[0035] Event-related potentials (ERPs) are potential changes in electroencephalograms (EEGs) triggered by a specific event (light stimulation). ERPs are obtained by averaging EEG signals recorded in multiple experiments and can reflect the brain's temporal and potential responses to specific stimuli.

[0036] By ensuring the LED light source and portable EEG headgear are calibrated to provide accurate stimulation and recording, and by adjusting the EEG headgear to the subject's head to ensure all six electrodes are precisely positioned in the visual cortex region, the subject is visually stimulated by activating the LED light source to display flashing light. Since the accuracy of the measurement results may be affected by the subject's subjective factors, the subject's EEG signals are collected and analyzed during the test to obtain more objective and accurate results. Furthermore, while the EEG acquisition device records the subject's EEG signals under visual stimulation in real time, the EEG data is affected by external factors such as eye movements and muscle movements during acquisition. Therefore, the signal processing unit filters and denoises the acquired EEG signals to accurately extract features related to visual stimulation as real-time feature signals. By analyzing these real-time feature signals and using ERP analysis to extract real-time features from the EEG signals, the visual stimulation parameters are dynamically adjusted to improve the effectiveness of visual stimulation and increase the stability of the test results.

[0037] This invention also provides a method for measuring the critical scintillation fusion frequency based on electroencephalography, comprising:

[0038] Step S1: Calibrate the LED light source and EEG headgear, adjust the EEG headgear to the subject's head, turn on the signal processing unit, and connect the LED light source and EEG headgear to the signal processing unit via Bluetooth or WiFi.

[0039] Step S2: Set an initial flashing frequency in the LED light source and start the LED light source to perform a visual stimulation process on the subject. The visual stimulation process is to emit a light beam at the initial flashing frequency or the current flashing frequency after adjustment, and generate a trigger command at each stimulation moment to send a trigger signal to the EEG acquisition device.

[0040] The initial flashing frequency is adjusted upward multiple times using a standard adjustment frequency to update the current flashing frequency, and the stimulation time is the time corresponding to each beam emission.

[0041] Step S3: The EEG signal of the subject under visual stimulation is acquired in real time through the EEG acquisition device, and the EEG signal is filtered and denoised to obtain the target EEG signal.

[0042] Step S4: The target EEG signal is segmented into several target EEG signal segments. Any target EEG signal segment is averaged to generate an ERP waveform. The relevant components in the ERP waveform are marked, and the key features in the ERP waveform are extracted. The relevant components include P1 wave, N1 wave and P2 wave. The key features include signal peak value, signal amplitude and signal delay.

[0043] The process of segmenting the target EEG signal is as follows:

[0044] Based on the time of stimulus occurrence, the target EEG signal is extracted for a preset stimulus duration to obtain the target EEG signal segment;

[0045] Step S5: Analyze the relevant components in any target EEG signal segment to determine whether the standard adjustment frequency should be adjusted.

[0046] Specifically, when the signal peak value is within the peak threshold range, real-time feature signals are extracted from the target EEG signal, and the real-time feature signals are matched in the data feature library to obtain real-time constant brightness feature signals and real-time flicker feature signals, so as to construct a perception flicker dataset and a perception constant brightness dataset.

[0047] Step S6: Analyze the constant brightness timestamps corresponding to the real-time constant brightness feature signals in the perceived constant brightness dataset based on the CFF feedback data to obtain the critical flicker fusion frequency value.

[0048] The CFF feedback data includes the CFF feedback time.

[0049] The start time of the real-time flashing feature signal is obtained to obtain the constant-brightness timestamp.

[0050] The technical solution of this utility model has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the protection scope of this utility model is obviously not limited to these specific embodiments. Without departing from the principle of this utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this utility model.

[0051] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A device for measuring the critical scintillation fusion frequency, characterized in that, include, LED light source, EEG acquisition device connected to the LED light source, and signal processing unit; The EEG acquisition device includes an EEG head-mounted device and electrodes disposed on the EEG head-mounted device.

2. The apparatus for measuring the critical scintillation fusion frequency according to claim 1, characterized in that, The electrodes are used to conduct brain signals.

3. The apparatus for measuring the critical scintillation fusion frequency according to claim 1, characterized in that, The LED light source includes a light-emitting module, a sleeve, and a threaded tube sleeved on the outside of the sleeve.

4. The apparatus for measuring the critical scintillation fusion frequency according to claim 3, characterized in that, The LED light source is connected to the EEG acquisition device via a connecting line.

5. The apparatus for measuring the critical scintillation fusion frequency according to claim 1, characterized in that, The signal processing unit is connected to the EEG acquisition device via Bluetooth or WiFi.

6. The apparatus for measuring the critical scintillation fusion frequency according to claim 1, characterized in that, It also includes a joystick and a feedback module, the feedback module being electrically connected to the joystick.

7. The apparatus for measuring the critical scintillation fusion frequency according to claim 6, characterized in that, The joystick includes a button and a communication module. The button is electrically connected to the signal processing unit, and the communication module is used to receive CFF feedback data from the button and transmit the CFF feedback data to the signal processing unit.

8. The apparatus for measuring the critical scintillation fusion frequency according to claim 1, characterized in that, The EEG head-mounted device remains fixed during the measurement process.

9. The apparatus for measuring the critical scintillation fusion frequency according to claim 2, characterized in that, The electrodes are positioned in the visual cortex region.

10. The apparatus for measuring the critical scintillation fusion frequency according to claim 9, characterized in that, The number of electrodes is 6.

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